Fuel cells can offer potentially clean, quiet and efficient power generation. Unlike thermal energy based engines, fuel cells use an electrochemical or battery-like process to convert the chemical energy associated with the conversion of hydrogen gas into water. Typically, in fuel cells, hydrogen gas and oxygen gas are fed into the anode and cathode of the fuel cell, respectively. At the anode, the hydrogen gas is electrochemically dissociated into hydrogen ions (H+) and free electrons (e−). The electrons flow out of the anode through an external electrical circuit. In polymer electrolyte membrane (PEM) fuel cells, in general, hydrogen ions (H+) formed at the anode flow to the cathode through the PEM electrolyte. At the cathode, oxygen gas fed into the cathode is electrochemically combined with the hydrogen ions and with the free electrons to generate water. In solid oxide fuel cells employing a solid oxide electrolyte, in general, oxygen ions are electrochemically formed at the cathode and move to the anode through the solid oxide electrolyte. The overall reaction in a fuel cell is as follows:2H2+O2→2H2O(vapor)+Energy  (1)Despite the advantages of clean and quiet power generation, fuel cell systems have faced a number of formidable market entry issues resulting from product immaturity, over-engineered system complexity, fuel efficiency, etc. Fuel efficiency can be increased by employing larger surface areas of the anode and cathode, or by increasing the number of fuel cells in a fuel stack. However, these approaches typically result in increases in the size of the fuel stack.
Therefore, there is a need for developing methods of increasing fuel efficiency in fuel cell systems without compromising the size of the fuel cell system, and for developing fuel cell systems having high fuel efficiency, and in particular fuel cell systems of relatively small size.